Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: Add clocksource_register_hz/khz interface
  posix-cpu-timers: Optimize run_posix_cpu_timers()
  time: Remove xtime_cache
  mqueue: Convert message queue timeout to use hrtimers
  hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIME
  timers: Introduce the concept of timer slack for legacy timers
  ntp: Remove tickadj
  ntp: Make time_adjust static
  time: Add xtime, wall_to_monotonic to feature-removal-schedule
  timer: Try to survive timer callback preempt_count leak
  timer: Split out timer function call
  timer: Print function name for timer callbacks modifying preemption count
  time: Clean up warp_clock()
  cpu-timers: Avoid iterating over all threads in fastpath_timer_check()
  cpu-timers: Change SIGEV_NONE timer implementation
  cpu-timers: Return correct previous timer reload value
  cpu-timers: Cleanup arm_timer()
  cpu-timers: Simplify RLIMIT_CPU handling

3 files changed, 65 insertions, 20 deletions

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 1f5dde637457..f08e99c1d561 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -625,6 +625,54 @@ static void clocksource_enqueue(struct clocksource *cs)
         list_add(&cs->list, entry);
 }
 
+
+/*
+ * Maximum time we expect to go between ticks. This includes idle
+ * tickless time. It provides the trade off between selecting a
+ * mult/shift pair that is very precise but can only handle a short
+ * period of time, vs. a mult/shift pair that can handle long periods
+ * of time but isn't as precise.
+ *
+ * This is a subsystem constant, and actual hardware limitations
+ * may override it (ie: clocksources that wrap every 3 seconds).
+ */
+#define MAX_UPDATE_LENGTH 5 /* Seconds */
+
+/**
+ * __clocksource_register_scale - Used to install new clocksources
+ * @t:          clocksource to be registered
+ * @scale:      Scale factor multiplied against freq to get clocksource hz
+ * @freq:       clocksource frequency (cycles per second) divided by scale
+ *
+ * Returns -EBUSY if registration fails, zero otherwise.
+ *
+ * This *SHOULD NOT* be called directly! Please use the
+ * clocksource_register_hz() or clocksource_register_khz helper functions.
+ */
+int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+{
+
+        /*
+         * Ideally we want to use  some of the limits used in
+         * clocksource_max_deferment, to provide a more informed
+         * MAX_UPDATE_LENGTH. But for now this just gets the
+         * register interface working properly.
+         */
+        clocks_calc_mult_shift(&cs->mult, &cs->shift, freq,
+                                      NSEC_PER_SEC/scale,
+                                      MAX_UPDATE_LENGTH*scale);
+        cs->max_idle_ns = clocksource_max_deferment(cs);
+
+        mutex_lock(&clocksource_mutex);
+        clocksource_enqueue(cs);
+        clocksource_select();
+        clocksource_enqueue_watchdog(cs);
+        mutex_unlock(&clocksource_mutex);
+        return 0;
+}
+EXPORT_SYMBOL_GPL(__clocksource_register_scale);
+
+
 /**
  * clocksource_register - Used to install new clocksources
  * @t:          clocksource to be registered
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 7c0f180d6e9d..c63116863a80 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -69,7 +69,7 @@ static s64			time_freq;
 /* time at last adjustment (secs):                                      */
 static long                     time_reftime;
 
-long                            time_adjust;
+static long                     time_adjust;
 
 /* constant (boot-param configurable) NTP tick adjustment (upscaled)    */
 static s64                      ntp_tick_adj;
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 39f6177fafac..caf8d4d4f5c8 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -165,13 +165,6 @@ struct timespec raw_time;
 /* flag for if timekeeping is suspended */
 int __read_mostly timekeeping_suspended;
 
-static struct timespec xtime_cache __attribute__ ((aligned (16)));
-void update_xtime_cache(u64 nsec)
-{
-        xtime_cache = xtime;
-        timespec_add_ns(&xtime_cache, nsec);
-}
-
 /* must hold xtime_lock */
 void timekeeping_leap_insert(int leapsecond)
 {
@@ -332,8 +325,6 @@ int do_settimeofday(struct timespec *tv)
 
         xtime = *tv;
 
-        update_xtime_cache(0);
-
         timekeeper.ntp_error = 0;
         ntp_clear();
 
@@ -559,7 +550,6 @@ void __init timekeeping_init(void)
         }
         set_normalized_timespec(&wall_to_monotonic,
                                 -boot.tv_sec, -boot.tv_nsec);
-        update_xtime_cache(0);
         total_sleep_time.tv_sec = 0;
         total_sleep_time.tv_nsec = 0;
         write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -593,7 +583,6 @@ static int timekeeping_resume(struct sys_device *dev)
                 wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
                 total_sleep_time = timespec_add_safe(total_sleep_time, ts);
         }
-        update_xtime_cache(0);
         /* re-base the last cycle value */
         timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
         timekeeper.ntp_error = 0;
@@ -788,7 +777,6 @@ void update_wall_time(void)
 {
         struct clocksource *clock;
         cycle_t offset;
-        u64 nsecs;
         int shift = 0, maxshift;
 
         /* Make sure we're fully resumed: */
@@ -847,7 +835,9 @@ void update_wall_time(void)
                 timekeeper.ntp_error += neg << timekeeper.ntp_error_shift;
         }
 
-        /* store full nanoseconds into xtime after rounding it up and
+
+        /*
+         * Store full nanoseconds into xtime after rounding it up and
          * add the remainder to the error difference.
          */
         xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1;
@@ -855,8 +845,15 @@ void update_wall_time(void)
         timekeeper.ntp_error += timekeeper.xtime_nsec <<
                                 timekeeper.ntp_error_shift;
 
-        nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
-        update_xtime_cache(nsecs);
+        /*
+         * Finally, make sure that after the rounding
+         * xtime.tv_nsec isn't larger then NSEC_PER_SEC
+         */
+        if (unlikely(xtime.tv_nsec >= NSEC_PER_SEC)) {
+                xtime.tv_nsec -= NSEC_PER_SEC;
+                xtime.tv_sec++;
+                second_overflow();
+        }
 
         /* check to see if there is a new clocksource to use */
         update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult);
@@ -896,13 +893,13 @@ EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
 
 unsigned long get_seconds(void)
 {
-        return xtime_cache.tv_sec;
+        return xtime.tv_sec;
 }
 EXPORT_SYMBOL(get_seconds);
 
 struct timespec __current_kernel_time(void)
 {
-        return xtime_cache;
+        return xtime;
 }
 
 struct timespec current_kernel_time(void)
@@ -913,7 +910,7 @@ struct timespec current_kernel_time(void)
         do {
                 seq = read_seqbegin(&xtime_lock);
 
-                now = xtime_cache;
+                now = xtime;
         } while (read_seqretry(&xtime_lock, seq));
 
         return now;
@@ -928,7 +925,7 @@ struct timespec get_monotonic_coarse(void)
         do {
                 seq = read_seqbegin(&xtime_lock);
 
-                now = xtime_cache;
+                now = xtime;
                 mono = wall_to_monotonic;
         } while (read_seqretry(&xtime_lock, seq));